need help in confidence interval plsss

A statistician fits a linear model of the form yi = α + βxi + εi to a set of data consisting of n = 16 pairs of observations (xi, yi). The sample mean of the x-values is equal to 0, and the statistician has calculated estimates a = 173.7 for α, b = 16.3 for β and S2 = 129.2 for σ2. In addition, Sxx = 261.0. Calculate the upper end of the 95% prediction interval for Y when x takes the value 6, giving your answer correct to 1 decimal place.